Textile apparatus



March 20, 1956 R. H. ROUGHSEDGE 2,738,937

TEXTILE APPARATUS Filed Oct. 6. 1951 F'IG.I.

INVENTOR. ROBERT H. ROUGHSEDGE United States Patent TEXTILE APPARATUS Robert H. Ronghsedge, Ramsey, N. 1., assignor to Celanese Corporation of America, New York, N. Y., a corporation of Delaware Application October 6, 1951, Serial No. 250,079

6 Claims. (Cl. 242-155) This invention relates to textile apparatus and relates more particularly to yarn tension devices for use in textile apparatus.

In my copending application Serial No. 166,020 filed June 3, 1950, now Patent No. 2,705,363, there is disclosed a novel yarn tension device in which the yarn tension is developed by the movement of an electric conductor through a magnetic field. In this device, the yarn is trained around a wheel which is rotatably mounted in any suitable manner and is operatively connected to a soft iron disc positioned adjacent one end of an electromagnet. As the yarn moves through the yarn tension device, with the electromagnet energized, it rotates the wheel around which it is trained, causing the soft iron disc to move through the magnetic field and thereby developing a braking force on the wheel and a tension in the yarn.

When the electromagnet of the yarn tension device described in my aforementioned application is energized, it develops a force tending to draw the soft iron disc axially toward the end of the electromagnet. This axial force produces considerable pressure on the bearings supporting the wheel to which the soft iron disc is operatively connected. With continued use, the pressure on the bearings will cause the same to wear, thereby producing a change in the braking force on the wheel and in the tension on the yarn. When a number of the yarn tension devices are operated together to develop tension in a plurality of ends of yarn, as in a warper, the changes in yarn tension due to wear will not be the same for all the ends of yarn. As a result, it is necessary to adjust the individual yarn tension devices periodically to avoid the production of defective warps. The labor involved in making these periodic adjustments of the yarn tension devices increases the cost of operating the textile apparatus in which said yarn tension devices are employed.

It is an important object of this invention to provide a yarn tension device which will be free from the foregoing and other difficulties and which will be especially simple in construction and eflicient in use.

A further object of this invention is to provide a yarn tension device which will maintain a substantially constant yarn tension without the necessity for periodic adjustments.

Another object of this invention is to provide a yarn tension device of the aforementioned type in which the magnetic forces are balanced so that they will not tend to produce any relative motion of the electric conductor and the magnetic field.

Other objects of this invention, together with certain details of construction and combinations of parts, will be apparent from the following detailed description and claims.

According to the present invention, there is provided a yarn tension device for applying tension to a travelling yarn comprising a member movable by said yarn, such as a rotatable wheel around which the yarn is adapted to be trained, and magnetic means for applying a braking force to said wheel to develop tension in the yarn without the Patented Mar. 20, 1956 use of friction. The magnetic braking means comprises a magnet and an electric conductor spaced from and out of contact with the magnet but positioned in the magnetic field produced by said magnet. Either the magnet or the electric conductor is fastened to the rotatable wheel so that, as the yarn causes said wheel to rotate, the electric conductor will be moved with respect to the magnetic field, generating an electric current therein. As is well known, the generation of an electric current in the condoctor will tend to oppose the motion of said conductor with respect to the magnetic field, thereby applying a braking force to the wheel to develop tension in the yarn. The magnet and electric conductor are so disposed with respect to one another that there will be no tendency for the magnetic field to move the electric conductor. As a result, there will be no extra pressures imposed on the hearings in the yarn tension device as the result of magnetic forces and the yarn tension device will develop a substantially uniform tension on the yarn without the necessity for periodic adjustments.

One suitable form of yarn tension device comprises an electromagnet having upper and lower pole pieces positioned parallel to one another and spaced apart. From the upper pole piece there projects downwardly a plurality of spaced teeth, arranged in a circle, which are separated from and interdigitated with a plurality of spaced teeth arranged in a circle and projecting upwardly from the lower pole piece. When the electromagnet is energized there will be produced a plurality of magnetic fields between the teeth of the upper and lower pole pieces. A ring of electrically conducting material, which ring may be formed of aluminum, copper or the like but which is preferably formed of a ferromagnetic material, is positioned concentrically oi the teeth of the upper and lower pole pieces and is centered vertically with respect to said pole pieces. The ring of ferromagnetic material is fastened in any suitable manner to the wheel around which the yarn is trained and, as the yarn is drawn through the yarn tension device and causes the said wheel to rotate, the ring of ferromagnetic material will be rotated with respect to the magnetic field developing a braking force on the wheel and a tension in the yarn. Because the magnet and electric conductor are disposed symmetrically with respect to one another, there will be no forces tending to move the said two elements toward each other and no extra pressures imposed on the hearings in the yarn tension device so that the yarn tension device will not require periodic adjustments to maintain a substantially uniform yarn tension.

A preferred embodiment of this invention is shown in the accompanying drawing wherein- Fig. 1 is a cross-sectional view of the yarn tension device,

Fig. 2 is a side elevational view of the yarn tension device with certain parts in cross-section, and

Fig. 3 is a detail cross-sectional view taken on the line 3-3 in Fig. 2 in the direction of the arrows.

Referring now to the drawing, the reference numeral 11 designates a wheel around which is trained a yarn 12 to which it is desired to apply tension. The periphery of the wheel 11 is divided into three sections, a lower section 13 that is tapered at a relatively sharp angle, an intermediate section 14 that is tapered at a smaller angle than the lower section 13, and an upper section 15 that is tapered at a smaller angle than the intermediate section 14. Because of the taper of the intermediate section 14, around which the yarn 12 is trained, the said yarn 12 tends to move upwardly on said section in passing around the periphery of the wheel 11, thereby preventing the overlapping of two turns of yarn with possible damage to or breakage of said yarn. Depending from the lower section 13 of the wheel 11 is a skirt 16 whose function will be set forth hereinafter. The wheel 11 is fastened to a hardened steel shaft 17 rotatably mounted in spaced, annular, oil-impregnated, sintered metal bearings 18 and 19 fitted within a bushing 20. The space 21 between the bearings 18 and 19 acts as a reservoir to receive the oil that tends to leave the bearings 18 and 19 during use and to return the said oil to the bearings. One end of shaft 17 bears against a hardened steel ball 22 which is held in place in the bearing 19 by means of a plug 23. Fitted to the bushing is a base plate 24 which supports an electromagnet indicated generally by reference numeral 25. a

The electromagnet comprises a coil 26 to which current is supplied through a lead 27. an upper pole piece 28 and a lower pole piece 29. The upper pole piece 28 has projecting downwardly therefrom a plurality of spaced teeth 31 arranged in a circle which are separated from and interdigitated with a plurality of spaced teeth 32 arranged in a circle and projecting upwardly from the lower pole piece 29. Mounted on the shaft 17 is a fitting 33 which carries a light aluminum flange 34 that fits snugly within the skirt 16 of the wheel 11 and is provided with a plurality of weight reducing perforations 35 therein. The skirt 16 on the wheel 11 and the flange 34 act effectively to prevent the yarn 12 from sliding under wheel 11 and coming into contact with the shaft 17 which would cause the said yarn 12 to break. A ring 36 of ferromagnetic material is mounted inside a depending rim 37 of the flange 34 concentric with the teeth 31 and 32 and centered with respect to the said teeth 31 and 32.

During use a current is caused to How through the coil 26 producing a magnetic field between the teeth 31 and 32 of the pole pieces 28 and 29, respectively. With the electromagnet 25 thus energized, movement of the yarn 12 through the yarn tension device which will cause the a wheel 11 to rotate thereby rotating the ring 36 with re spect to the magnetic field between the teeth 31 and 32. The movement of the ring 36 with respect to the magnetic field will produce a braking force tending to oppose the rotation of the wheel 11 and thereby impose a tension on the yarn 12. Because the electromagnet 25 is disposed symmetrically of the ring 36 there will be no tendency for any relative movement to occur between said elements and, as a result, no extra pressure on the bearings supporting the shaft 17 due to the magnetic forces. The yarn tension device will, accordingly, maintain a substantially uniform yarn tension without the necessity for periodic adjustment.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of my invention.

1 claim:

1. A yarn tension device comprising a magnet including a circular coil, means movable by a traveling yarn, a vertical shaft supporting said yarn movable means, a bearing supporting the lower end of said vertical shaft, a circular rim operatively connected to said yarn movable means, and a ring of electrically conducting material secured to said rim and positioned in the magnetic field produced by said magnet so that movement of the yarn movable means by the traveling yarn will move said ring with respect to the magnetic field to apply a braking force to said yarn movable means whereby tension is ap plied to the yarn, said ring of electrically conducting material being disposed concentrically about the vertical axis of said coil and symmetrically of said coil in the horizontal plane so that tendency for the magnetic field produced by the magnet to move the ring of electrically conducting material and apply pressure on the bearing will be avoided.

2. A yarn tension device comprising a magnet including a circular coil, a ring of ferromagnetic material positioned in the magnetic field produced by said magnet. means movable by a travelling yarn to move the ring of ferromagnetic material with respect to the magnetic field to apply a braking force to said yarn movable means whereby tension is applied to the yarn, a vertical shaft supporting said yarn movable means, and a bearing supporting the lower end of said vertical shaft, said ring of ferromagnetic material being disposed concentrically of said coil of said magnet about a vertical axis so that tendency for the magnetic field produced by the magnet to move the ring of ferromagnetic material toward said magnet and apply additional pressure on the bearing will be avoided.

3. A yarn tension device comprising a magnet including a circular coil, means movable by a traveling yarn, a vertical shaft supporting said yarn movable means, a bearing supporting the lower end of said vertical shaft, a circular rim operatively connected to said yarn movable means, and a ring of ferromagnetic material secured to said rim and positioned in the magnetic field produced by said magnet so that movement of the yarn movable means by the traveling yarn will move said ring with respect to the magnetic field to apply a braking force to said yarn movable means whereby tension is applied to the yarn, said ring of ferromagnetic material being disposed concentrically about the vertical axis of said coil and symmetrically of said coil in the horizontal plane so that tendency for the magnetic field produced by the magnet to move the ring of ferromagnetic material and apply pressure on the bearing will be avoided.

4. A yarn tension device comprising a magnet having upper and lower pole pieces circular in form, a ring of electrically conducting material positioned in the magnetic field produced by said magnet, means movable by a travelling yarn to move the ring of electrically conducting material with respect to the magnetic field to apply a braking force to said yarn movable means whereby tension is applied to the yarn, a vertical shaft supporting said yarn movable means, and a bearing supporting the lower end of said vertical shaft, said ring of electrically conducting matcrial being disposed concentrically about a vertical axis and symmetrically with respect to said magnet in the horizontal plane so that tendency for the magnetic field produced by the magnet to move the ring of electrically conducting material and apply additional pressure on the hearing will be avoided.

5. A yarn tension device comprising a magnet having upper and lower pole pieces, a plurality of spaced teeth arranged in a circle projecting downwardly from the upper pole piece, a plurality of spaced teeth arranged in a circle projecting upwardly from the lower pole piece separated from and interdigitating with the teeth projecting from the upper pole piece, a ring of electrically conducting material positioned in the magnetic field produced by said magnet, means movable by a travelling yarn to move the ring of electrically conducting material with respect to the magnetic field to apply a braking force to said yarn movable means whereby tension is applied to the yarn. a vertical shaft supporting said yarn movable means, and a bearing supporting the lower end of said vertical Shaft, said ring of electrically conducting material being disposed concentrically and symmetrically with respect to said magnet so that tendency for the magnetic field produced by the magnet to move the ring of electrically conducting material and apply additional pressure on the bearing will be avoided.

6. A yarn tension device comprising a magnet having upper and lower pole pieces, a plurality of spaced teeth arranged in a circle projecting downwardly from the upper pole piece, a plurality of spaced teeth arranged in a circle projecting upwardly from the lower pole piece separated from and interdigitating with the teeth projecting from the upper pole piece, a ring of ferromagnetic material positioned in the magnetic field produced by said magnet, means movable by a travelling yarn to move the ring of ferromagnetic material with respect to the magnetic field to apply a braking force to said yarn movable means whereby tension is applied to the yarn, a vertical shaft supfor the magnetic field produced by the magnet to move 5 the ring of ferromagnetic material and apply additional pressure on the bearing will be avoided.

References Cited in the file of this patent UNITED STATES PATENTS 1,528,796 Simmons Mar. 10, 1925 6 Johnson Aug. 25, Ransom Oct. 24, Nelson Dec. 12, Romine Mar. 29, Miller Sept. 20, Bullard et a1 Aug. 22, Gibbs et a1 Oct. 31, Duryee Sept. 14,

FOREIGN PATENTS Great Britain Dec. 14, Great Britain Mar. 10, 

1. A YARN TENSION DEVICE COMPRISING A MAGNET INCLUDING A CIRCULAR COIL, MEANS MOVABLE BY A TRAVELING YARN, A VERTICAL SHAFT SUPPORTING SAID YARN MOVABLE MEANS, A BEARING SUPPORTING THE LOWER END OF SAID VERTICAL SHAFT, A CIRCULAR RIM OPERATIVELY CONNECTED TO SAID YARN MOVABLE MEANS, AND A RING OF ELECTRICALLY CONDUCTING MATERIAL SECURED TO SAID RIM AND POSITIONED IN THE MAGNETIC FIELD PRODUCED BY SAID MAGNET SO THAT MOVEMENT OF THE YARN MOVABLE MEANS BY THE TRAVLEING YARN WILL MOVE SIAD RING WITH RESPECT TO THE MAGNETIC FIELD TO APPLY A BRAKING 